Rotors for turbomachines must satisfy a variety of requirements and boundary conditions. For example, it is necessary that individual rotor stages be balanced to be able to be operated at a low rate of wear and with little maintenance, especially at high rotational speeds. Imbalances often occur in individual rotor stages as a function of the manufacturing process and, in particular, can be induced during rotor blade milling. The rotor blades can thereby be manufactured in what is generally referred to as BLISK form or in individual blade form. The imbalances are normally compensated prior to a first operational use by appropriate balancing measures, for example, by static or dynamic balancing.
Furthermore, possible accumulations of oil in cavities in the inner rotor space, such as accumulations of bearing oil, should be able to flow off from the inner rotor space in the case of rotors for turbomachines, for example, in aircraft engine applications, to ensure that cabin air streams are not potentially contaminated by discharges from the compressor. Suitable design approaches are needed to fulfill both requirements.